Fix invalid code in select_content_dialog.js
Fix invalid code in select_content_dialog.js

fixes: PLAT-4914

This should have never worked, because it was trying to access a 
`const` variable before it was initialized but babel erroneously made it
work because it transpiled those `const`s down to `var`s.

Test plan:
* you should not get errors about 
  ReferenceError: Cannot access 't' before initialization
  When you run this code

Change-Id: Id669b931c985a9874b9f391971452b3c83a99f58
Reviewed-on: https://gerrit.instructure.com/209654
Tested-by: Jenkins
Reviewed-by: Marc Phillips <b810f855174e0bc032432310b0808df2cf714fbc@instructure.com>
Reviewed-by: Xander Moffatt <27f70fe194da423604e6e0a63a3de19814736fa9@instructure.com>
QA-Review: Tucker Mcknight <4b51b98c1d84aa97854d216bd061ce5d3eda8a28@instructure.com>
Product-Review: Ryan Shaw <ea3cd978650417470535f3a4725b6b5042a6ab59@instructure.com>

sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,djbender/canvas-lms